1 /*
2  *   This file is provided under a GPLv2 license.  When using or
3  *   redistributing this file, you may do so under that license.
4  *
5  *   GPL LICENSE SUMMARY
6  *
7  *   Copyright (C) 2016 T-Platforms. All Rights Reserved.
8  *
9  *   This program is free software; you can redistribute it and/or modify it
10  *   under the terms and conditions of the GNU General Public License,
11  *   version 2, as published by the Free Software Foundation.
12  *
13  *   This program is distributed in the hope that it will be useful, but WITHOUT
14  *   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15  *   FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
16  *   more details.
17  *
18  *   You should have received a copy of the GNU General Public License along
19  *   with this program; if not, it can be found <http://www.gnu.org/licenses/>.
20  *
21  *   The full GNU General Public License is included in this distribution in
22  *   the file called "COPYING".
23  *
24  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
25  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
26  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
27  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
28  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
29  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
30  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
34  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35  *
36  * IDT PCIe-switch NTB Linux driver
37  *
38  * Contact Information:
39  * Serge Semin <fancer.lancer@gmail.com>, <Sergey.Semin@t-platforms.ru>
40  */
41 /*
42  *           NOTE of the IDT 89HPESx SMBus-slave interface driver
43  *    This driver primarily is developed to have an access to EEPROM device of
44  * IDT PCIe-switches. IDT provides a simple SMBus interface to perform IO-
45  * operations from/to EEPROM, which is located at private (so called Master)
46  * SMBus of switches. Using that interface this the driver creates a simple
47  * binary sysfs-file in the device directory:
48  * /sys/bus/i2c/devices/<bus>-<devaddr>/eeprom
49  * In case if read-only flag is specified in the dts-node of device desription,
50  * User-space applications won't be able to write to the EEPROM sysfs-node.
51  *    Additionally IDT 89HPESx SMBus interface has an ability to write/read
52  * data of device CSRs. This driver exposes debugf-file to perform simple IO
53  * operations using that ability for just basic debug purpose. Particularly
54  * next file is created in the specific debugfs-directory:
55  * /sys/kernel/debug/idt_csr/
56  * Format of the debugfs-node is:
57  * $ cat /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>;
58  * <CSR address>:<CSR value>
59  * So reading the content of the file gives current CSR address and it value.
60  * If User-space application wishes to change current CSR address,
61  * it can just write a proper value to the sysfs-file:
62  * $ echo "<CSR address>" > /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>
63  * If it wants to change the CSR value as well, the format of the write
64  * operation is:
65  * $ echo "<CSR address>:<CSR value>" > \
66  *        /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>;
67  * CSR address and value can be any of hexadecimal, decimal or octal format.
68  */
69 
70 #include <linux/kernel.h>
71 #include <linux/init.h>
72 #include <linux/module.h>
73 #include <linux/types.h>
74 #include <linux/sizes.h>
75 #include <linux/slab.h>
76 #include <linux/mutex.h>
77 #include <linux/sysfs.h>
78 #include <linux/debugfs.h>
79 #include <linux/mod_devicetable.h>
80 #include <linux/property.h>
81 #include <linux/i2c.h>
82 #include <linux/pci_ids.h>
83 #include <linux/delay.h>
84 
85 #define IDT_NAME		"89hpesx"
86 #define IDT_89HPESX_DESC	"IDT 89HPESx SMBus-slave interface driver"
87 #define IDT_89HPESX_VER		"1.0"
88 
89 MODULE_DESCRIPTION(IDT_89HPESX_DESC);
90 MODULE_VERSION(IDT_89HPESX_VER);
91 MODULE_LICENSE("GPL v2");
92 MODULE_AUTHOR("T-platforms");
93 
94 /*
95  * csr_dbgdir - CSR read/write operations Debugfs directory
96  */
97 static struct dentry *csr_dbgdir;
98 
99 /*
100  * struct idt_89hpesx_dev - IDT 89HPESx device data structure
101  * @eesize:	Size of EEPROM in bytes (calculated from "idt,eecompatible")
102  * @eero:	EEPROM Read-only flag
103  * @eeaddr:	EEPROM custom address
104  *
105  * @inieecmd:	Initial cmd value for EEPROM read/write operations
106  * @inicsrcmd:	Initial cmd value for CSR read/write operations
107  * @iniccode:	Initialial command code value for IO-operations
108  *
109  * @csr:	CSR address to perform read operation
110  *
111  * @smb_write:	SMBus write method
112  * @smb_read:	SMBus read method
113  * @smb_mtx:	SMBus mutex
114  *
115  * @client:	i2c client used to perform IO operations
116  *
117  * @ee_file:	EEPROM read/write sysfs-file
118  * @csr_file:	CSR read/write debugfs-node
119  */
120 struct idt_smb_seq;
121 struct idt_89hpesx_dev {
122 	u32 eesize;
123 	bool eero;
124 	u8 eeaddr;
125 
126 	u8 inieecmd;
127 	u8 inicsrcmd;
128 	u8 iniccode;
129 
130 	u16 csr;
131 
132 	int (*smb_write)(struct idt_89hpesx_dev *, const struct idt_smb_seq *);
133 	int (*smb_read)(struct idt_89hpesx_dev *, struct idt_smb_seq *);
134 	struct mutex smb_mtx;
135 
136 	struct i2c_client *client;
137 
138 	struct bin_attribute *ee_file;
139 	struct dentry *csr_dir;
140 	struct dentry *csr_file;
141 };
142 
143 /*
144  * struct idt_smb_seq - sequence of data to be read/written from/to IDT 89HPESx
145  * @ccode:	SMBus command code
146  * @bytecnt:	Byte count of operation
147  * @data:	Data to by written
148  */
149 struct idt_smb_seq {
150 	u8 ccode;
151 	u8 bytecnt;
152 	u8 *data;
153 };
154 
155 /*
156  * struct idt_eeprom_seq - sequence of data to be read/written from/to EEPROM
157  * @cmd:	Transaction CMD
158  * @eeaddr:	EEPROM custom address
159  * @memaddr:	Internal memory address of EEPROM
160  * @data:	Data to be written at the memory address
161  */
162 struct idt_eeprom_seq {
163 	u8 cmd;
164 	u8 eeaddr;
165 	u16 memaddr;
166 	u8 data;
167 } __packed;
168 
169 /*
170  * struct idt_csr_seq - sequence of data to be read/written from/to CSR
171  * @cmd:	Transaction CMD
172  * @csraddr:	Internal IDT device CSR address
173  * @data:	Data to be read/written from/to the CSR address
174  */
175 struct idt_csr_seq {
176 	u8 cmd;
177 	u16 csraddr;
178 	u32 data;
179 } __packed;
180 
181 /*
182  * SMBus command code macros
183  * @CCODE_END:		Indicates the end of transaction
184  * @CCODE_START:	Indicates the start of transaction
185  * @CCODE_CSR:		CSR read/write transaction
186  * @CCODE_EEPROM:	EEPROM read/write transaction
187  * @CCODE_BYTE:		Supplied data has BYTE length
188  * @CCODE_WORD:		Supplied data has WORD length
189  * @CCODE_BLOCK:	Supplied data has variable length passed in bytecnt
190  *			byte right following CCODE byte
191  */
192 #define CCODE_END	((u8)0x01)
193 #define CCODE_START	((u8)0x02)
194 #define CCODE_CSR	((u8)0x00)
195 #define CCODE_EEPROM	((u8)0x04)
196 #define CCODE_BYTE	((u8)0x00)
197 #define CCODE_WORD	((u8)0x20)
198 #define CCODE_BLOCK	((u8)0x40)
199 #define CCODE_PEC	((u8)0x80)
200 
201 /*
202  * EEPROM command macros
203  * @EEPROM_OP_WRITE:	EEPROM write operation
204  * @EEPROM_OP_READ:	EEPROM read operation
205  * @EEPROM_USA:		Use specified address of EEPROM
206  * @EEPROM_NAERR:	EEPROM device is not ready to respond
207  * @EEPROM_LAERR:	EEPROM arbitration loss error
208  * @EEPROM_MSS:		EEPROM misplace start & stop bits error
209  * @EEPROM_WR_CNT:	Bytes count to perform write operation
210  * @EEPROM_WRRD_CNT:	Bytes count to write before reading
211  * @EEPROM_RD_CNT:	Bytes count to perform read operation
212  * @EEPROM_DEF_SIZE:	Fall back size of EEPROM
213  * @EEPROM_DEF_ADDR:	Defatul EEPROM address
214  * @EEPROM_TOUT:	Timeout before retry read operation if eeprom is busy
215  */
216 #define EEPROM_OP_WRITE	((u8)0x00)
217 #define EEPROM_OP_READ	((u8)0x01)
218 #define EEPROM_USA	((u8)0x02)
219 #define EEPROM_NAERR	((u8)0x08)
220 #define EEPROM_LAERR    ((u8)0x10)
221 #define EEPROM_MSS	((u8)0x20)
222 #define EEPROM_WR_CNT	((u8)5)
223 #define EEPROM_WRRD_CNT	((u8)4)
224 #define EEPROM_RD_CNT	((u8)5)
225 #define EEPROM_DEF_SIZE	((u16)4096)
226 #define EEPROM_DEF_ADDR	((u8)0x50)
227 #define EEPROM_TOUT	(100)
228 
229 /*
230  * CSR command macros
231  * @CSR_DWE:		Enable all four bytes of the operation
232  * @CSR_OP_WRITE:	CSR write operation
233  * @CSR_OP_READ:	CSR read operation
234  * @CSR_RERR:		Read operation error
235  * @CSR_WERR:		Write operation error
236  * @CSR_WR_CNT:		Bytes count to perform write operation
237  * @CSR_WRRD_CNT:	Bytes count to write before reading
238  * @CSR_RD_CNT:		Bytes count to perform read operation
239  * @CSR_MAX:		Maximum CSR address
240  * @CSR_DEF:		Default CSR address
241  * @CSR_REAL_ADDR:	CSR real unshifted address
242  */
243 #define CSR_DWE			((u8)0x0F)
244 #define CSR_OP_WRITE		((u8)0x00)
245 #define CSR_OP_READ		((u8)0x10)
246 #define CSR_RERR		((u8)0x40)
247 #define CSR_WERR		((u8)0x80)
248 #define CSR_WR_CNT		((u8)7)
249 #define CSR_WRRD_CNT		((u8)3)
250 #define CSR_RD_CNT		((u8)7)
251 #define CSR_MAX			((u32)0x3FFFF)
252 #define CSR_DEF			((u16)0x0000)
253 #define CSR_REAL_ADDR(val)	((unsigned int)val << 2)
254 
255 /*
256  * IDT 89HPESx basic register
257  * @IDT_VIDDID_CSR:	PCIe VID and DID of IDT 89HPESx
258  * @IDT_VID_MASK:	Mask of VID
259  */
260 #define IDT_VIDDID_CSR	((u32)0x0000)
261 #define IDT_VID_MASK	((u32)0xFFFF)
262 
263 /*
264  * IDT 89HPESx can send NACK when new command is sent before previous one
265  * fininshed execution. In this case driver retries operation
266  * certain times.
267  * @RETRY_CNT:		Number of retries before giving up and fail
268  * @idt_smb_safe:	Generate a retry loop on corresponding SMBus method
269  */
270 #define RETRY_CNT (128)
271 #define idt_smb_safe(ops, args...) ({ \
272 	int __retry = RETRY_CNT; \
273 	s32 __sts; \
274 	do { \
275 		__sts = i2c_smbus_ ## ops ## _data(args); \
276 	} while (__retry-- && __sts < 0); \
277 	__sts; \
278 })
279 
280 /*===========================================================================
281  *                         i2c bus level IO-operations
282  *===========================================================================
283  */
284 
285 /*
286  * idt_smb_write_byte() - SMBus write method when I2C_SMBUS_BYTE_DATA operation
287  *                        is only available
288  * @pdev:	Pointer to the driver data
289  * @seq:	Sequence of data to be written
290  */
291 static int idt_smb_write_byte(struct idt_89hpesx_dev *pdev,
292 			      const struct idt_smb_seq *seq)
293 {
294 	s32 sts;
295 	u8 ccode;
296 	int idx;
297 
298 	/* Loop over the supplied data sending byte one-by-one */
299 	for (idx = 0; idx < seq->bytecnt; idx++) {
300 		/* Collect the command code byte */
301 		ccode = seq->ccode | CCODE_BYTE;
302 		if (idx == 0)
303 			ccode |= CCODE_START;
304 		if (idx == seq->bytecnt - 1)
305 			ccode |= CCODE_END;
306 
307 		/* Send data to the device */
308 		sts = idt_smb_safe(write_byte, pdev->client, ccode,
309 			seq->data[idx]);
310 		if (sts != 0)
311 			return (int)sts;
312 	}
313 
314 	return 0;
315 }
316 
317 /*
318  * idt_smb_read_byte() - SMBus read method when I2C_SMBUS_BYTE_DATA operation
319  *                        is only available
320  * @pdev:	Pointer to the driver data
321  * @seq:	Buffer to read data to
322  */
323 static int idt_smb_read_byte(struct idt_89hpesx_dev *pdev,
324 			     struct idt_smb_seq *seq)
325 {
326 	s32 sts;
327 	u8 ccode;
328 	int idx;
329 
330 	/* Loop over the supplied buffer receiving byte one-by-one */
331 	for (idx = 0; idx < seq->bytecnt; idx++) {
332 		/* Collect the command code byte */
333 		ccode = seq->ccode | CCODE_BYTE;
334 		if (idx == 0)
335 			ccode |= CCODE_START;
336 		if (idx == seq->bytecnt - 1)
337 			ccode |= CCODE_END;
338 
339 		/* Read data from the device */
340 		sts = idt_smb_safe(read_byte, pdev->client, ccode);
341 		if (sts < 0)
342 			return (int)sts;
343 
344 		seq->data[idx] = (u8)sts;
345 	}
346 
347 	return 0;
348 }
349 
350 /*
351  * idt_smb_write_word() - SMBus write method when I2C_SMBUS_BYTE_DATA and
352  *                        I2C_FUNC_SMBUS_WORD_DATA operations are available
353  * @pdev:	Pointer to the driver data
354  * @seq:	Sequence of data to be written
355  */
356 static int idt_smb_write_word(struct idt_89hpesx_dev *pdev,
357 			      const struct idt_smb_seq *seq)
358 {
359 	s32 sts;
360 	u8 ccode;
361 	int idx, evencnt;
362 
363 	/* Calculate the even count of data to send */
364 	evencnt = seq->bytecnt - (seq->bytecnt % 2);
365 
366 	/* Loop over the supplied data sending two bytes at a time */
367 	for (idx = 0; idx < evencnt; idx += 2) {
368 		/* Collect the command code byte */
369 		ccode = seq->ccode | CCODE_WORD;
370 		if (idx == 0)
371 			ccode |= CCODE_START;
372 		if (idx == evencnt - 2)
373 			ccode |= CCODE_END;
374 
375 		/* Send word data to the device */
376 		sts = idt_smb_safe(write_word, pdev->client, ccode,
377 			*(u16 *)&seq->data[idx]);
378 		if (sts != 0)
379 			return (int)sts;
380 	}
381 
382 	/* If there is odd number of bytes then send just one last byte */
383 	if (seq->bytecnt != evencnt) {
384 		/* Collect the command code byte */
385 		ccode = seq->ccode | CCODE_BYTE | CCODE_END;
386 		if (idx == 0)
387 			ccode |= CCODE_START;
388 
389 		/* Send byte data to the device */
390 		sts = idt_smb_safe(write_byte, pdev->client, ccode,
391 			seq->data[idx]);
392 		if (sts != 0)
393 			return (int)sts;
394 	}
395 
396 	return 0;
397 }
398 
399 /*
400  * idt_smb_read_word() - SMBus read method when I2C_SMBUS_BYTE_DATA and
401  *                       I2C_FUNC_SMBUS_WORD_DATA operations are available
402  * @pdev:	Pointer to the driver data
403  * @seq:	Buffer to read data to
404  */
405 static int idt_smb_read_word(struct idt_89hpesx_dev *pdev,
406 			     struct idt_smb_seq *seq)
407 {
408 	s32 sts;
409 	u8 ccode;
410 	int idx, evencnt;
411 
412 	/* Calculate the even count of data to send */
413 	evencnt = seq->bytecnt - (seq->bytecnt % 2);
414 
415 	/* Loop over the supplied data reading two bytes at a time */
416 	for (idx = 0; idx < evencnt; idx += 2) {
417 		/* Collect the command code byte */
418 		ccode = seq->ccode | CCODE_WORD;
419 		if (idx == 0)
420 			ccode |= CCODE_START;
421 		if (idx == evencnt - 2)
422 			ccode |= CCODE_END;
423 
424 		/* Read word data from the device */
425 		sts = idt_smb_safe(read_word, pdev->client, ccode);
426 		if (sts < 0)
427 			return (int)sts;
428 
429 		*(u16 *)&seq->data[idx] = (u16)sts;
430 	}
431 
432 	/* If there is odd number of bytes then receive just one last byte */
433 	if (seq->bytecnt != evencnt) {
434 		/* Collect the command code byte */
435 		ccode = seq->ccode | CCODE_BYTE | CCODE_END;
436 		if (idx == 0)
437 			ccode |= CCODE_START;
438 
439 		/* Read last data byte from the device */
440 		sts = idt_smb_safe(read_byte, pdev->client, ccode);
441 		if (sts < 0)
442 			return (int)sts;
443 
444 		seq->data[idx] = (u8)sts;
445 	}
446 
447 	return 0;
448 }
449 
450 /*
451  * idt_smb_write_block() - SMBus write method when I2C_SMBUS_BLOCK_DATA
452  *                         operation is available
453  * @pdev:	Pointer to the driver data
454  * @seq:	Sequence of data to be written
455  */
456 static int idt_smb_write_block(struct idt_89hpesx_dev *pdev,
457 			       const struct idt_smb_seq *seq)
458 {
459 	u8 ccode;
460 
461 	/* Return error if too much data passed to send */
462 	if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
463 		return -EINVAL;
464 
465 	/* Collect the command code byte */
466 	ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
467 
468 	/* Send block of data to the device */
469 	return idt_smb_safe(write_block, pdev->client, ccode, seq->bytecnt,
470 		seq->data);
471 }
472 
473 /*
474  * idt_smb_read_block() - SMBus read method when I2C_SMBUS_BLOCK_DATA
475  *                        operation is available
476  * @pdev:	Pointer to the driver data
477  * @seq:	Buffer to read data to
478  */
479 static int idt_smb_read_block(struct idt_89hpesx_dev *pdev,
480 			      struct idt_smb_seq *seq)
481 {
482 	s32 sts;
483 	u8 ccode;
484 
485 	/* Return error if too much data passed to send */
486 	if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
487 		return -EINVAL;
488 
489 	/* Collect the command code byte */
490 	ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
491 
492 	/* Read block of data from the device */
493 	sts = idt_smb_safe(read_block, pdev->client, ccode, seq->data);
494 	if (sts != seq->bytecnt)
495 		return (sts < 0 ? sts : -ENODATA);
496 
497 	return 0;
498 }
499 
500 /*
501  * idt_smb_write_i2c_block() - SMBus write method when I2C_SMBUS_I2C_BLOCK_DATA
502  *                             operation is available
503  * @pdev:	Pointer to the driver data
504  * @seq:	Sequence of data to be written
505  *
506  * NOTE It's usual SMBus write block operation, except the actual data length is
507  * sent as first byte of data
508  */
509 static int idt_smb_write_i2c_block(struct idt_89hpesx_dev *pdev,
510 				   const struct idt_smb_seq *seq)
511 {
512 	u8 ccode, buf[I2C_SMBUS_BLOCK_MAX + 1];
513 
514 	/* Return error if too much data passed to send */
515 	if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
516 		return -EINVAL;
517 
518 	/* Collect the data to send. Length byte must be added prior the data */
519 	buf[0] = seq->bytecnt;
520 	memcpy(&buf[1], seq->data, seq->bytecnt);
521 
522 	/* Collect the command code byte */
523 	ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
524 
525 	/* Send length and block of data to the device */
526 	return idt_smb_safe(write_i2c_block, pdev->client, ccode,
527 		seq->bytecnt + 1, buf);
528 }
529 
530 /*
531  * idt_smb_read_i2c_block() - SMBus read method when I2C_SMBUS_I2C_BLOCK_DATA
532  *                            operation is available
533  * @pdev:	Pointer to the driver data
534  * @seq:	Buffer to read data to
535  *
536  * NOTE It's usual SMBus read block operation, except the actual data length is
537  * retrieved as first byte of data
538  */
539 static int idt_smb_read_i2c_block(struct idt_89hpesx_dev *pdev,
540 				  struct idt_smb_seq *seq)
541 {
542 	u8 ccode, buf[I2C_SMBUS_BLOCK_MAX + 1];
543 	s32 sts;
544 
545 	/* Return error if too much data passed to send */
546 	if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
547 		return -EINVAL;
548 
549 	/* Collect the command code byte */
550 	ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
551 
552 	/* Read length and block of data from the device */
553 	sts = idt_smb_safe(read_i2c_block, pdev->client, ccode,
554 		seq->bytecnt + 1, buf);
555 	if (sts != seq->bytecnt + 1)
556 		return (sts < 0 ? sts : -ENODATA);
557 	if (buf[0] != seq->bytecnt)
558 		return -ENODATA;
559 
560 	/* Copy retrieved data to the output data buffer */
561 	memcpy(seq->data, &buf[1], seq->bytecnt);
562 
563 	return 0;
564 }
565 
566 /*===========================================================================
567  *                          EEPROM IO-operations
568  *===========================================================================
569  */
570 
571 /*
572  * idt_eeprom_read_byte() - read just one byte from EEPROM
573  * @pdev:	Pointer to the driver data
574  * @memaddr:	Start EEPROM memory address
575  * @data:	Data to be written to EEPROM
576  */
577 static int idt_eeprom_read_byte(struct idt_89hpesx_dev *pdev, u16 memaddr,
578 				u8 *data)
579 {
580 	struct device *dev = &pdev->client->dev;
581 	struct idt_eeprom_seq eeseq;
582 	struct idt_smb_seq smbseq;
583 	int ret, retry;
584 
585 	/* Initialize SMBus sequence fields */
586 	smbseq.ccode = pdev->iniccode | CCODE_EEPROM;
587 	smbseq.data = (u8 *)&eeseq;
588 
589 	/*
590 	 * Sometimes EEPROM may respond with NACK if it's busy with previous
591 	 * operation, so we need to perform a few attempts of read cycle
592 	 */
593 	retry = RETRY_CNT;
594 	do {
595 		/* Send EEPROM memory address to read data from */
596 		smbseq.bytecnt = EEPROM_WRRD_CNT;
597 		eeseq.cmd = pdev->inieecmd | EEPROM_OP_READ;
598 		eeseq.eeaddr = pdev->eeaddr;
599 		eeseq.memaddr = cpu_to_le16(memaddr);
600 		ret = pdev->smb_write(pdev, &smbseq);
601 		if (ret != 0) {
602 			dev_err(dev, "Failed to init eeprom addr 0x%02hhx",
603 				memaddr);
604 			break;
605 		}
606 
607 		/* Perform read operation */
608 		smbseq.bytecnt = EEPROM_RD_CNT;
609 		ret = pdev->smb_read(pdev, &smbseq);
610 		if (ret != 0) {
611 			dev_err(dev, "Failed to read eeprom data 0x%02hhx",
612 				memaddr);
613 			break;
614 		}
615 
616 		/* Restart read operation if the device is busy */
617 		if (retry && (eeseq.cmd & EEPROM_NAERR)) {
618 			dev_dbg(dev, "EEPROM busy, retry reading after %d ms",
619 				EEPROM_TOUT);
620 			msleep(EEPROM_TOUT);
621 			continue;
622 		}
623 
624 		/* Check whether IDT successfully read data from EEPROM */
625 		if (eeseq.cmd & (EEPROM_NAERR | EEPROM_LAERR | EEPROM_MSS)) {
626 			dev_err(dev,
627 				"Communication with eeprom failed, cmd 0x%hhx",
628 				eeseq.cmd);
629 			ret = -EREMOTEIO;
630 			break;
631 		}
632 
633 		/* Save retrieved data and exit the loop */
634 		*data = eeseq.data;
635 		break;
636 	} while (retry--);
637 
638 	/* Return the status of operation */
639 	return ret;
640 }
641 
642 /*
643  * idt_eeprom_write() - EEPROM write operation
644  * @pdev:	Pointer to the driver data
645  * @memaddr:	Start EEPROM memory address
646  * @len:	Length of data to be written
647  * @data:	Data to be written to EEPROM
648  */
649 static int idt_eeprom_write(struct idt_89hpesx_dev *pdev, u16 memaddr, u16 len,
650 			    const u8 *data)
651 {
652 	struct device *dev = &pdev->client->dev;
653 	struct idt_eeprom_seq eeseq;
654 	struct idt_smb_seq smbseq;
655 	int ret;
656 	u16 idx;
657 
658 	/* Initialize SMBus sequence fields */
659 	smbseq.ccode = pdev->iniccode | CCODE_EEPROM;
660 	smbseq.data = (u8 *)&eeseq;
661 
662 	/* Send data byte-by-byte, checking if it is successfully written */
663 	for (idx = 0; idx < len; idx++, memaddr++) {
664 		/* Lock IDT SMBus device */
665 		mutex_lock(&pdev->smb_mtx);
666 
667 		/* Perform write operation */
668 		smbseq.bytecnt = EEPROM_WR_CNT;
669 		eeseq.cmd = pdev->inieecmd | EEPROM_OP_WRITE;
670 		eeseq.eeaddr = pdev->eeaddr;
671 		eeseq.memaddr = cpu_to_le16(memaddr);
672 		eeseq.data = data[idx];
673 		ret = pdev->smb_write(pdev, &smbseq);
674 		if (ret != 0) {
675 			dev_err(dev,
676 				"Failed to write 0x%04hx:0x%02hhx to eeprom",
677 				memaddr, data[idx]);
678 			goto err_mutex_unlock;
679 		}
680 
681 		/*
682 		 * Check whether the data is successfully written by reading
683 		 * from the same EEPROM memory address.
684 		 */
685 		eeseq.data = ~data[idx];
686 		ret = idt_eeprom_read_byte(pdev, memaddr, &eeseq.data);
687 		if (ret != 0)
688 			goto err_mutex_unlock;
689 
690 		/* Check whether the read byte is the same as written one */
691 		if (eeseq.data != data[idx]) {
692 			dev_err(dev, "Values don't match 0x%02hhx != 0x%02hhx",
693 				eeseq.data, data[idx]);
694 			ret = -EREMOTEIO;
695 			goto err_mutex_unlock;
696 		}
697 
698 		/* Unlock IDT SMBus device */
699 err_mutex_unlock:
700 		mutex_unlock(&pdev->smb_mtx);
701 		if (ret != 0)
702 			return ret;
703 	}
704 
705 	return 0;
706 }
707 
708 /*
709  * idt_eeprom_read() - EEPROM read operation
710  * @pdev:	Pointer to the driver data
711  * @memaddr:	Start EEPROM memory address
712  * @len:	Length of data to read
713  * @buf:	Buffer to read data to
714  */
715 static int idt_eeprom_read(struct idt_89hpesx_dev *pdev, u16 memaddr, u16 len,
716 			   u8 *buf)
717 {
718 	int ret;
719 	u16 idx;
720 
721 	/* Read data byte-by-byte, retrying if it wasn't successful */
722 	for (idx = 0; idx < len; idx++, memaddr++) {
723 		/* Lock IDT SMBus device */
724 		mutex_lock(&pdev->smb_mtx);
725 
726 		/* Just read the byte to the buffer */
727 		ret = idt_eeprom_read_byte(pdev, memaddr, &buf[idx]);
728 
729 		/* Unlock IDT SMBus device */
730 		mutex_unlock(&pdev->smb_mtx);
731 
732 		/* Return error if read operation failed */
733 		if (ret != 0)
734 			return ret;
735 	}
736 
737 	return 0;
738 }
739 
740 /*===========================================================================
741  *                          CSR IO-operations
742  *===========================================================================
743  */
744 
745 /*
746  * idt_csr_write() - CSR write operation
747  * @pdev:	Pointer to the driver data
748  * @csraddr:	CSR address (with no two LS bits)
749  * @data:	Data to be written to CSR
750  */
751 static int idt_csr_write(struct idt_89hpesx_dev *pdev, u16 csraddr,
752 			 const u32 data)
753 {
754 	struct device *dev = &pdev->client->dev;
755 	struct idt_csr_seq csrseq;
756 	struct idt_smb_seq smbseq;
757 	int ret;
758 
759 	/* Initialize SMBus sequence fields */
760 	smbseq.ccode = pdev->iniccode | CCODE_CSR;
761 	smbseq.data = (u8 *)&csrseq;
762 
763 	/* Lock IDT SMBus device */
764 	mutex_lock(&pdev->smb_mtx);
765 
766 	/* Perform write operation */
767 	smbseq.bytecnt = CSR_WR_CNT;
768 	csrseq.cmd = pdev->inicsrcmd | CSR_OP_WRITE;
769 	csrseq.csraddr = cpu_to_le16(csraddr);
770 	csrseq.data = cpu_to_le32(data);
771 	ret = pdev->smb_write(pdev, &smbseq);
772 	if (ret != 0) {
773 		dev_err(dev, "Failed to write 0x%04x: 0x%04x to csr",
774 			CSR_REAL_ADDR(csraddr), data);
775 		goto err_mutex_unlock;
776 	}
777 
778 	/* Send CSR address to read data from */
779 	smbseq.bytecnt = CSR_WRRD_CNT;
780 	csrseq.cmd = pdev->inicsrcmd | CSR_OP_READ;
781 	ret = pdev->smb_write(pdev, &smbseq);
782 	if (ret != 0) {
783 		dev_err(dev, "Failed to init csr address 0x%04x",
784 			CSR_REAL_ADDR(csraddr));
785 		goto err_mutex_unlock;
786 	}
787 
788 	/* Perform read operation */
789 	smbseq.bytecnt = CSR_RD_CNT;
790 	ret = pdev->smb_read(pdev, &smbseq);
791 	if (ret != 0) {
792 		dev_err(dev, "Failed to read csr 0x%04x",
793 			CSR_REAL_ADDR(csraddr));
794 		goto err_mutex_unlock;
795 	}
796 
797 	/* Check whether IDT successfully retrieved CSR data */
798 	if (csrseq.cmd & (CSR_RERR | CSR_WERR)) {
799 		dev_err(dev, "IDT failed to perform CSR r/w");
800 		ret = -EREMOTEIO;
801 		goto err_mutex_unlock;
802 	}
803 
804 	/* Unlock IDT SMBus device */
805 err_mutex_unlock:
806 	mutex_unlock(&pdev->smb_mtx);
807 
808 	return ret;
809 }
810 
811 /*
812  * idt_csr_read() - CSR read operation
813  * @pdev:	Pointer to the driver data
814  * @csraddr:	CSR address (with no two LS bits)
815  * @data:	Data to be written to CSR
816  */
817 static int idt_csr_read(struct idt_89hpesx_dev *pdev, u16 csraddr, u32 *data)
818 {
819 	struct device *dev = &pdev->client->dev;
820 	struct idt_csr_seq csrseq;
821 	struct idt_smb_seq smbseq;
822 	int ret;
823 
824 	/* Initialize SMBus sequence fields */
825 	smbseq.ccode = pdev->iniccode | CCODE_CSR;
826 	smbseq.data = (u8 *)&csrseq;
827 
828 	/* Lock IDT SMBus device */
829 	mutex_lock(&pdev->smb_mtx);
830 
831 	/* Send CSR register address before reading it */
832 	smbseq.bytecnt = CSR_WRRD_CNT;
833 	csrseq.cmd = pdev->inicsrcmd | CSR_OP_READ;
834 	csrseq.csraddr = cpu_to_le16(csraddr);
835 	ret = pdev->smb_write(pdev, &smbseq);
836 	if (ret != 0) {
837 		dev_err(dev, "Failed to init csr address 0x%04x",
838 			CSR_REAL_ADDR(csraddr));
839 		goto err_mutex_unlock;
840 	}
841 
842 	/* Perform read operation */
843 	smbseq.bytecnt = CSR_RD_CNT;
844 	ret = pdev->smb_read(pdev, &smbseq);
845 	if (ret != 0) {
846 		dev_err(dev, "Failed to read csr 0x%04hx",
847 			CSR_REAL_ADDR(csraddr));
848 		goto err_mutex_unlock;
849 	}
850 
851 	/* Check whether IDT successfully retrieved CSR data */
852 	if (csrseq.cmd & (CSR_RERR | CSR_WERR)) {
853 		dev_err(dev, "IDT failed to perform CSR r/w");
854 		ret = -EREMOTEIO;
855 		goto err_mutex_unlock;
856 	}
857 
858 	/* Save data retrieved from IDT */
859 	*data = le32_to_cpu(csrseq.data);
860 
861 	/* Unlock IDT SMBus device */
862 err_mutex_unlock:
863 	mutex_unlock(&pdev->smb_mtx);
864 
865 	return ret;
866 }
867 
868 /*===========================================================================
869  *                          Sysfs/debugfs-nodes IO-operations
870  *===========================================================================
871  */
872 
873 /*
874  * eeprom_write() - EEPROM sysfs-node write callback
875  * @filep:	Pointer to the file system node
876  * @kobj:	Pointer to the kernel object related to the sysfs-node
877  * @attr:	Attributes of the file
878  * @buf:	Buffer to write data to
879  * @off:	Offset at which data should be written to
880  * @count:	Number of bytes to write
881  */
882 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
883 			    struct bin_attribute *attr,
884 			    char *buf, loff_t off, size_t count)
885 {
886 	struct idt_89hpesx_dev *pdev;
887 	int ret;
888 
889 	/* Retrieve driver data */
890 	pdev = dev_get_drvdata(kobj_to_dev(kobj));
891 
892 	/* Perform EEPROM write operation */
893 	ret = idt_eeprom_write(pdev, (u16)off, (u16)count, (u8 *)buf);
894 	return (ret != 0 ? ret : count);
895 }
896 
897 /*
898  * eeprom_read() - EEPROM sysfs-node read callback
899  * @filep:	Pointer to the file system node
900  * @kobj:	Pointer to the kernel object related to the sysfs-node
901  * @attr:	Attributes of the file
902  * @buf:	Buffer to write data to
903  * @off:	Offset at which data should be written to
904  * @count:	Number of bytes to write
905  */
906 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
907 			   struct bin_attribute *attr,
908 			   char *buf, loff_t off, size_t count)
909 {
910 	struct idt_89hpesx_dev *pdev;
911 	int ret;
912 
913 	/* Retrieve driver data */
914 	pdev = dev_get_drvdata(kobj_to_dev(kobj));
915 
916 	/* Perform EEPROM read operation */
917 	ret = idt_eeprom_read(pdev, (u16)off, (u16)count, (u8 *)buf);
918 	return (ret != 0 ? ret : count);
919 }
920 
921 /*
922  * idt_dbgfs_csr_write() - CSR debugfs-node write callback
923  * @filep:	Pointer to the file system file descriptor
924  * @buf:	Buffer to read data from
925  * @count:	Size of the buffer
926  * @offp:	Offset within the file
927  *
928  * It accepts either "0x<reg addr>:0x<value>" for saving register address
929  * and writing value to specified DWORD register or "0x<reg addr>" for
930  * just saving register address in order to perform next read operation.
931  *
932  * WARNING No spaces are allowed. Incoming string must be strictly formated as:
933  * "<reg addr>:<value>". Register address must be aligned within 4 bytes
934  * (one DWORD).
935  */
936 static ssize_t idt_dbgfs_csr_write(struct file *filep, const char __user *ubuf,
937 				   size_t count, loff_t *offp)
938 {
939 	struct idt_89hpesx_dev *pdev = filep->private_data;
940 	char *colon_ch, *csraddr_str, *csrval_str;
941 	int ret, csraddr_len;
942 	u32 csraddr, csrval;
943 	char *buf;
944 
945 	/* Copy data from User-space */
946 	buf = kmalloc(count + 1, GFP_KERNEL);
947 	if (!buf)
948 		return -ENOMEM;
949 
950 	ret = simple_write_to_buffer(buf, count, offp, ubuf, count);
951 	if (ret < 0)
952 		goto free_buf;
953 	buf[count] = 0;
954 
955 	/* Find position of colon in the buffer */
956 	colon_ch = strnchr(buf, count, ':');
957 
958 	/*
959 	 * If there is colon passed then new CSR value should be parsed as
960 	 * well, so allocate buffer for CSR address substring.
961 	 * If no colon is found, then string must have just one number with
962 	 * no new CSR value
963 	 */
964 	if (colon_ch != NULL) {
965 		csraddr_len = colon_ch - buf;
966 		csraddr_str =
967 			kmalloc(csraddr_len + 1, GFP_KERNEL);
968 		if (csraddr_str == NULL) {
969 			ret = -ENOMEM;
970 			goto free_buf;
971 		}
972 		/* Copy the register address to the substring buffer */
973 		strncpy(csraddr_str, buf, csraddr_len);
974 		csraddr_str[csraddr_len] = '\0';
975 		/* Register value must follow the colon */
976 		csrval_str = colon_ch + 1;
977 	} else /* if (str_colon == NULL) */ {
978 		csraddr_str = (char *)buf; /* Just to shut warning up */
979 		csraddr_len = strnlen(csraddr_str, count);
980 		csrval_str = NULL;
981 	}
982 
983 	/* Convert CSR address to u32 value */
984 	ret = kstrtou32(csraddr_str, 0, &csraddr);
985 	if (ret != 0)
986 		goto free_csraddr_str;
987 
988 	/* Check whether passed register address is valid */
989 	if (csraddr > CSR_MAX || !IS_ALIGNED(csraddr, SZ_4)) {
990 		ret = -EINVAL;
991 		goto free_csraddr_str;
992 	}
993 
994 	/* Shift register address to the right so to have u16 address */
995 	pdev->csr = (csraddr >> 2);
996 
997 	/* Parse new CSR value and send it to IDT, if colon has been found */
998 	if (colon_ch != NULL) {
999 		ret = kstrtou32(csrval_str, 0, &csrval);
1000 		if (ret != 0)
1001 			goto free_csraddr_str;
1002 
1003 		ret = idt_csr_write(pdev, pdev->csr, csrval);
1004 		if (ret != 0)
1005 			goto free_csraddr_str;
1006 	}
1007 
1008 	/* Free memory only if colon has been found */
1009 free_csraddr_str:
1010 	if (colon_ch != NULL)
1011 		kfree(csraddr_str);
1012 
1013 	/* Free buffer allocated for data retrieved from User-space */
1014 free_buf:
1015 	kfree(buf);
1016 
1017 	return (ret != 0 ? ret : count);
1018 }
1019 
1020 /*
1021  * idt_dbgfs_csr_read() - CSR debugfs-node read callback
1022  * @filep:	Pointer to the file system file descriptor
1023  * @buf:	Buffer to write data to
1024  * @count:	Size of the buffer
1025  * @offp:	Offset within the file
1026  *
1027  * It just prints the pair "0x<reg addr>:0x<value>" to passed buffer.
1028  */
1029 #define CSRBUF_SIZE	((size_t)32)
1030 static ssize_t idt_dbgfs_csr_read(struct file *filep, char __user *ubuf,
1031 				  size_t count, loff_t *offp)
1032 {
1033 	struct idt_89hpesx_dev *pdev = filep->private_data;
1034 	u32 csraddr, csrval;
1035 	char buf[CSRBUF_SIZE];
1036 	int ret, size;
1037 
1038 	/* Perform CSR read operation */
1039 	ret = idt_csr_read(pdev, pdev->csr, &csrval);
1040 	if (ret != 0)
1041 		return ret;
1042 
1043 	/* Shift register address to the left so to have real address */
1044 	csraddr = ((u32)pdev->csr << 2);
1045 
1046 	/* Print the "0x<reg addr>:0x<value>" to buffer */
1047 	size = snprintf(buf, CSRBUF_SIZE, "0x%05x:0x%08x\n",
1048 		(unsigned int)csraddr, (unsigned int)csrval);
1049 
1050 	/* Copy data to User-space */
1051 	return simple_read_from_buffer(ubuf, count, offp, buf, size);
1052 }
1053 
1054 /*
1055  * eeprom_attribute - EEPROM sysfs-node attributes
1056  *
1057  * NOTE Size will be changed in compliance with OF node. EEPROM attribute will
1058  * be read-only as well if the corresponding flag is specified in OF node.
1059  */
1060 static BIN_ATTR_RW(eeprom, EEPROM_DEF_SIZE);
1061 
1062 /*
1063  * csr_dbgfs_ops - CSR debugfs-node read/write operations
1064  */
1065 static const struct file_operations csr_dbgfs_ops = {
1066 	.owner = THIS_MODULE,
1067 	.open = simple_open,
1068 	.write = idt_dbgfs_csr_write,
1069 	.read = idt_dbgfs_csr_read
1070 };
1071 
1072 /*===========================================================================
1073  *                       Driver init/deinit methods
1074  *===========================================================================
1075  */
1076 
1077 /*
1078  * idt_set_defval() - disable EEPROM access by default
1079  * @pdev:	Pointer to the driver data
1080  */
1081 static void idt_set_defval(struct idt_89hpesx_dev *pdev)
1082 {
1083 	/* If OF info is missing then use next values */
1084 	pdev->eesize = 0;
1085 	pdev->eero = true;
1086 	pdev->inieecmd = 0;
1087 	pdev->eeaddr = 0;
1088 }
1089 
1090 static const struct i2c_device_id ee_ids[];
1091 
1092 /*
1093  * idt_ee_match_id() - check whether the node belongs to compatible EEPROMs
1094  */
1095 static const struct i2c_device_id *idt_ee_match_id(struct fwnode_handle *fwnode)
1096 {
1097 	const struct i2c_device_id *id = ee_ids;
1098 	const char *compatible, *p;
1099 	char devname[I2C_NAME_SIZE];
1100 	int ret;
1101 
1102 	ret = fwnode_property_read_string(fwnode, "compatible", &compatible);
1103 	if (ret)
1104 		return NULL;
1105 
1106 	p = strchr(compatible, ',');
1107 	strlcpy(devname, p ? p + 1 : compatible, sizeof(devname));
1108 	/* Search through the device name */
1109 	while (id->name[0]) {
1110 		if (strcmp(devname, id->name) == 0)
1111 			return id;
1112 		id++;
1113 	}
1114 	return NULL;
1115 }
1116 
1117 /*
1118  * idt_get_fw_data() - get IDT i2c-device parameters from device tree
1119  * @pdev:	Pointer to the driver data
1120  */
1121 static void idt_get_fw_data(struct idt_89hpesx_dev *pdev)
1122 {
1123 	struct device *dev = &pdev->client->dev;
1124 	struct fwnode_handle *fwnode;
1125 	const struct i2c_device_id *ee_id = NULL;
1126 	u32 eeprom_addr;
1127 	int ret;
1128 
1129 	device_for_each_child_node(dev, fwnode) {
1130 		ee_id = idt_ee_match_id(fwnode);
1131 		if (!ee_id) {
1132 			dev_warn(dev, "Skip unsupported EEPROM device");
1133 			continue;
1134 		} else
1135 			break;
1136 	}
1137 
1138 	/* If there is no fwnode EEPROM device, then set zero size */
1139 	if (!ee_id) {
1140 		dev_warn(dev, "No fwnode, EEPROM access disabled");
1141 		idt_set_defval(pdev);
1142 		return;
1143 	}
1144 
1145 	/* Retrieve EEPROM size */
1146 	pdev->eesize = (u32)ee_id->driver_data;
1147 
1148 	/* Get custom EEPROM address from 'reg' attribute */
1149 	ret = fwnode_property_read_u32(fwnode, "reg", &eeprom_addr);
1150 	if (ret || (eeprom_addr == 0)) {
1151 		dev_warn(dev, "No EEPROM reg found, use default address 0x%x",
1152 			 EEPROM_DEF_ADDR);
1153 		pdev->inieecmd = 0;
1154 		pdev->eeaddr = EEPROM_DEF_ADDR << 1;
1155 	} else {
1156 		pdev->inieecmd = EEPROM_USA;
1157 		pdev->eeaddr = eeprom_addr << 1;
1158 	}
1159 
1160 	/* Check EEPROM 'read-only' flag */
1161 	if (fwnode_property_read_bool(fwnode, "read-only"))
1162 		pdev->eero = true;
1163 	else /* if (!fwnode_property_read_bool(node, "read-only")) */
1164 		pdev->eero = false;
1165 
1166 	dev_info(dev, "EEPROM of %d bytes found by 0x%x",
1167 		pdev->eesize, pdev->eeaddr);
1168 }
1169 
1170 /*
1171  * idt_create_pdev() - create and init data structure of the driver
1172  * @client:	i2c client of IDT PCIe-switch device
1173  */
1174 static struct idt_89hpesx_dev *idt_create_pdev(struct i2c_client *client)
1175 {
1176 	struct idt_89hpesx_dev *pdev;
1177 
1178 	/* Allocate memory for driver data */
1179 	pdev = devm_kmalloc(&client->dev, sizeof(struct idt_89hpesx_dev),
1180 		GFP_KERNEL);
1181 	if (pdev == NULL)
1182 		return ERR_PTR(-ENOMEM);
1183 
1184 	/* Initialize basic fields of the data */
1185 	pdev->client = client;
1186 	i2c_set_clientdata(client, pdev);
1187 
1188 	/* Read firmware nodes information */
1189 	idt_get_fw_data(pdev);
1190 
1191 	/* Initialize basic CSR CMD field - use full DWORD-sized r/w ops */
1192 	pdev->inicsrcmd = CSR_DWE;
1193 	pdev->csr = CSR_DEF;
1194 
1195 	/* Enable Packet Error Checking if it's supported by adapter */
1196 	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_PEC)) {
1197 		pdev->iniccode = CCODE_PEC;
1198 		client->flags |= I2C_CLIENT_PEC;
1199 	} else /* PEC is unsupported */ {
1200 		pdev->iniccode = 0;
1201 	}
1202 
1203 	return pdev;
1204 }
1205 
1206 /*
1207  * idt_free_pdev() - free data structure of the driver
1208  * @pdev:	Pointer to the driver data
1209  */
1210 static void idt_free_pdev(struct idt_89hpesx_dev *pdev)
1211 {
1212 	/* Clear driver data from device private field */
1213 	i2c_set_clientdata(pdev->client, NULL);
1214 }
1215 
1216 /*
1217  * idt_set_smbus_ops() - set supported SMBus operations
1218  * @pdev:	Pointer to the driver data
1219  * Return status of smbus check operations
1220  */
1221 static int idt_set_smbus_ops(struct idt_89hpesx_dev *pdev)
1222 {
1223 	struct i2c_adapter *adapter = pdev->client->adapter;
1224 	struct device *dev = &pdev->client->dev;
1225 
1226 	/* Check i2c adapter read functionality */
1227 	if (i2c_check_functionality(adapter,
1228 				    I2C_FUNC_SMBUS_READ_BLOCK_DATA)) {
1229 		pdev->smb_read = idt_smb_read_block;
1230 		dev_dbg(dev, "SMBus block-read op chosen");
1231 	} else if (i2c_check_functionality(adapter,
1232 					   I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
1233 		pdev->smb_read = idt_smb_read_i2c_block;
1234 		dev_dbg(dev, "SMBus i2c-block-read op chosen");
1235 	} else if (i2c_check_functionality(adapter,
1236 					   I2C_FUNC_SMBUS_READ_WORD_DATA) &&
1237 		   i2c_check_functionality(adapter,
1238 					   I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
1239 		pdev->smb_read = idt_smb_read_word;
1240 		dev_warn(dev, "Use slow word/byte SMBus read ops");
1241 	} else if (i2c_check_functionality(adapter,
1242 					   I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
1243 		pdev->smb_read = idt_smb_read_byte;
1244 		dev_warn(dev, "Use slow byte SMBus read op");
1245 	} else /* no supported smbus read operations */ {
1246 		dev_err(dev, "No supported SMBus read op");
1247 		return -EPFNOSUPPORT;
1248 	}
1249 
1250 	/* Check i2c adapter write functionality */
1251 	if (i2c_check_functionality(adapter,
1252 				    I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)) {
1253 		pdev->smb_write = idt_smb_write_block;
1254 		dev_dbg(dev, "SMBus block-write op chosen");
1255 	} else if (i2c_check_functionality(adapter,
1256 					   I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {
1257 		pdev->smb_write = idt_smb_write_i2c_block;
1258 		dev_dbg(dev, "SMBus i2c-block-write op chosen");
1259 	} else if (i2c_check_functionality(adapter,
1260 					   I2C_FUNC_SMBUS_WRITE_WORD_DATA) &&
1261 		   i2c_check_functionality(adapter,
1262 					   I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
1263 		pdev->smb_write = idt_smb_write_word;
1264 		dev_warn(dev, "Use slow word/byte SMBus write op");
1265 	} else if (i2c_check_functionality(adapter,
1266 					   I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
1267 		pdev->smb_write = idt_smb_write_byte;
1268 		dev_warn(dev, "Use slow byte SMBus write op");
1269 	} else /* no supported smbus write operations */ {
1270 		dev_err(dev, "No supported SMBus write op");
1271 		return -EPFNOSUPPORT;
1272 	}
1273 
1274 	/* Initialize IDT SMBus slave interface mutex */
1275 	mutex_init(&pdev->smb_mtx);
1276 
1277 	return 0;
1278 }
1279 
1280 /*
1281  * idt_check_dev() - check whether it's really IDT 89HPESx device
1282  * @pdev:	Pointer to the driver data
1283  * Return status of i2c adapter check operation
1284  */
1285 static int idt_check_dev(struct idt_89hpesx_dev *pdev)
1286 {
1287 	struct device *dev = &pdev->client->dev;
1288 	u32 viddid;
1289 	int ret;
1290 
1291 	/* Read VID and DID directly from IDT memory space */
1292 	ret = idt_csr_read(pdev, IDT_VIDDID_CSR, &viddid);
1293 	if (ret != 0) {
1294 		dev_err(dev, "Failed to read VID/DID");
1295 		return ret;
1296 	}
1297 
1298 	/* Check whether it's IDT device */
1299 	if ((viddid & IDT_VID_MASK) != PCI_VENDOR_ID_IDT) {
1300 		dev_err(dev, "Got unsupported VID/DID: 0x%08x", viddid);
1301 		return -ENODEV;
1302 	}
1303 
1304 	dev_info(dev, "Found IDT 89HPES device VID:0x%04x, DID:0x%04x",
1305 		(viddid & IDT_VID_MASK), (viddid >> 16));
1306 
1307 	return 0;
1308 }
1309 
1310 /*
1311  * idt_create_sysfs_files() - create sysfs attribute files
1312  * @pdev:	Pointer to the driver data
1313  * Return status of operation
1314  */
1315 static int idt_create_sysfs_files(struct idt_89hpesx_dev *pdev)
1316 {
1317 	struct device *dev = &pdev->client->dev;
1318 	int ret;
1319 
1320 	/* Don't do anything if EEPROM isn't accessible */
1321 	if (pdev->eesize == 0) {
1322 		dev_dbg(dev, "Skip creating sysfs-files");
1323 		return 0;
1324 	}
1325 
1326 	/* Allocate memory for attribute file */
1327 	pdev->ee_file = devm_kmalloc(dev, sizeof(*pdev->ee_file), GFP_KERNEL);
1328 	if (!pdev->ee_file)
1329 		return -ENOMEM;
1330 
1331 	/* Copy the declared EEPROM attr structure to change some of fields */
1332 	memcpy(pdev->ee_file, &bin_attr_eeprom, sizeof(*pdev->ee_file));
1333 
1334 	/* In case of read-only EEPROM get rid of write ability */
1335 	if (pdev->eero) {
1336 		pdev->ee_file->attr.mode &= ~0200;
1337 		pdev->ee_file->write = NULL;
1338 	}
1339 	/* Create EEPROM sysfs file */
1340 	pdev->ee_file->size = pdev->eesize;
1341 	ret = sysfs_create_bin_file(&dev->kobj, pdev->ee_file);
1342 	if (ret != 0) {
1343 		dev_err(dev, "Failed to create EEPROM sysfs-node");
1344 		return ret;
1345 	}
1346 
1347 	return 0;
1348 }
1349 
1350 /*
1351  * idt_remove_sysfs_files() - remove sysfs attribute files
1352  * @pdev:	Pointer to the driver data
1353  */
1354 static void idt_remove_sysfs_files(struct idt_89hpesx_dev *pdev)
1355 {
1356 	struct device *dev = &pdev->client->dev;
1357 
1358 	/* Don't do anything if EEPROM wasn't accessible */
1359 	if (pdev->eesize == 0)
1360 		return;
1361 
1362 	/* Remove EEPROM sysfs file */
1363 	sysfs_remove_bin_file(&dev->kobj, pdev->ee_file);
1364 }
1365 
1366 /*
1367  * idt_create_dbgfs_files() - create debugfs files
1368  * @pdev:	Pointer to the driver data
1369  */
1370 #define CSRNAME_LEN	((size_t)32)
1371 static void idt_create_dbgfs_files(struct idt_89hpesx_dev *pdev)
1372 {
1373 	struct i2c_client *cli = pdev->client;
1374 	char fname[CSRNAME_LEN];
1375 
1376 	/* Create Debugfs directory for CSR file */
1377 	snprintf(fname, CSRNAME_LEN, "%d-%04hx", cli->adapter->nr, cli->addr);
1378 	pdev->csr_dir = debugfs_create_dir(fname, csr_dbgdir);
1379 
1380 	/* Create Debugfs file for CSR read/write operations */
1381 	pdev->csr_file = debugfs_create_file(cli->name, 0600,
1382 		pdev->csr_dir, pdev, &csr_dbgfs_ops);
1383 }
1384 
1385 /*
1386  * idt_remove_dbgfs_files() - remove debugfs files
1387  * @pdev:	Pointer to the driver data
1388  */
1389 static void idt_remove_dbgfs_files(struct idt_89hpesx_dev *pdev)
1390 {
1391 	/* Remove CSR directory and it sysfs-node */
1392 	debugfs_remove_recursive(pdev->csr_dir);
1393 }
1394 
1395 /*
1396  * idt_probe() - IDT 89HPESx driver probe() callback method
1397  */
1398 static int idt_probe(struct i2c_client *client, const struct i2c_device_id *id)
1399 {
1400 	struct idt_89hpesx_dev *pdev;
1401 	int ret;
1402 
1403 	/* Create driver data */
1404 	pdev = idt_create_pdev(client);
1405 	if (IS_ERR(pdev))
1406 		return PTR_ERR(pdev);
1407 
1408 	/* Set SMBus operations */
1409 	ret = idt_set_smbus_ops(pdev);
1410 	if (ret != 0)
1411 		goto err_free_pdev;
1412 
1413 	/* Check whether it is truly IDT 89HPESx device */
1414 	ret = idt_check_dev(pdev);
1415 	if (ret != 0)
1416 		goto err_free_pdev;
1417 
1418 	/* Create sysfs files */
1419 	ret = idt_create_sysfs_files(pdev);
1420 	if (ret != 0)
1421 		goto err_free_pdev;
1422 
1423 	/* Create debugfs files */
1424 	idt_create_dbgfs_files(pdev);
1425 
1426 	return 0;
1427 
1428 err_free_pdev:
1429 	idt_free_pdev(pdev);
1430 
1431 	return ret;
1432 }
1433 
1434 /*
1435  * idt_remove() - IDT 89HPESx driver remove() callback method
1436  */
1437 static int idt_remove(struct i2c_client *client)
1438 {
1439 	struct idt_89hpesx_dev *pdev = i2c_get_clientdata(client);
1440 
1441 	/* Remove debugfs files first */
1442 	idt_remove_dbgfs_files(pdev);
1443 
1444 	/* Remove sysfs files */
1445 	idt_remove_sysfs_files(pdev);
1446 
1447 	/* Discard driver data structure */
1448 	idt_free_pdev(pdev);
1449 
1450 	return 0;
1451 }
1452 
1453 /*
1454  * ee_ids - array of supported EEPROMs
1455  */
1456 static const struct i2c_device_id ee_ids[] = {
1457 	{ "24c32",  4096},
1458 	{ "24c64",  8192},
1459 	{ "24c128", 16384},
1460 	{ "24c256", 32768},
1461 	{ "24c512", 65536},
1462 	{}
1463 };
1464 MODULE_DEVICE_TABLE(i2c, ee_ids);
1465 
1466 /*
1467  * idt_ids - supported IDT 89HPESx devices
1468  */
1469 static const struct i2c_device_id idt_ids[] = {
1470 	{ "89hpes8nt2", 0 },
1471 	{ "89hpes12nt3", 0 },
1472 
1473 	{ "89hpes24nt6ag2", 0 },
1474 	{ "89hpes32nt8ag2", 0 },
1475 	{ "89hpes32nt8bg2", 0 },
1476 	{ "89hpes12nt12g2", 0 },
1477 	{ "89hpes16nt16g2", 0 },
1478 	{ "89hpes24nt24g2", 0 },
1479 	{ "89hpes32nt24ag2", 0 },
1480 	{ "89hpes32nt24bg2", 0 },
1481 
1482 	{ "89hpes12n3", 0 },
1483 	{ "89hpes12n3a", 0 },
1484 	{ "89hpes24n3", 0 },
1485 	{ "89hpes24n3a", 0 },
1486 
1487 	{ "89hpes32h8", 0 },
1488 	{ "89hpes32h8g2", 0 },
1489 	{ "89hpes48h12", 0 },
1490 	{ "89hpes48h12g2", 0 },
1491 	{ "89hpes48h12ag2", 0 },
1492 	{ "89hpes16h16", 0 },
1493 	{ "89hpes22h16", 0 },
1494 	{ "89hpes22h16g2", 0 },
1495 	{ "89hpes34h16", 0 },
1496 	{ "89hpes34h16g2", 0 },
1497 	{ "89hpes64h16", 0 },
1498 	{ "89hpes64h16g2", 0 },
1499 	{ "89hpes64h16ag2", 0 },
1500 
1501 	/* { "89hpes3t3", 0 }, // No SMBus-slave iface */
1502 	{ "89hpes12t3g2", 0 },
1503 	{ "89hpes24t3g2", 0 },
1504 	/* { "89hpes4t4", 0 }, // No SMBus-slave iface */
1505 	{ "89hpes16t4", 0 },
1506 	{ "89hpes4t4g2", 0 },
1507 	{ "89hpes10t4g2", 0 },
1508 	{ "89hpes16t4g2", 0 },
1509 	{ "89hpes16t4ag2", 0 },
1510 	{ "89hpes5t5", 0 },
1511 	{ "89hpes6t5", 0 },
1512 	{ "89hpes8t5", 0 },
1513 	{ "89hpes8t5a", 0 },
1514 	{ "89hpes24t6", 0 },
1515 	{ "89hpes6t6g2", 0 },
1516 	{ "89hpes24t6g2", 0 },
1517 	{ "89hpes16t7", 0 },
1518 	{ "89hpes32t8", 0 },
1519 	{ "89hpes32t8g2", 0 },
1520 	{ "89hpes48t12", 0 },
1521 	{ "89hpes48t12g2", 0 },
1522 	{ /* END OF LIST */ }
1523 };
1524 MODULE_DEVICE_TABLE(i2c, idt_ids);
1525 
1526 static const struct of_device_id idt_of_match[] = {
1527 	{ .compatible = "idt,89hpes8nt2", },
1528 	{ .compatible = "idt,89hpes12nt3", },
1529 
1530 	{ .compatible = "idt,89hpes24nt6ag2", },
1531 	{ .compatible = "idt,89hpes32nt8ag2", },
1532 	{ .compatible = "idt,89hpes32nt8bg2", },
1533 	{ .compatible = "idt,89hpes12nt12g2", },
1534 	{ .compatible = "idt,89hpes16nt16g2", },
1535 	{ .compatible = "idt,89hpes24nt24g2", },
1536 	{ .compatible = "idt,89hpes32nt24ag2", },
1537 	{ .compatible = "idt,89hpes32nt24bg2", },
1538 
1539 	{ .compatible = "idt,89hpes12n3", },
1540 	{ .compatible = "idt,89hpes12n3a", },
1541 	{ .compatible = "idt,89hpes24n3", },
1542 	{ .compatible = "idt,89hpes24n3a", },
1543 
1544 	{ .compatible = "idt,89hpes32h8", },
1545 	{ .compatible = "idt,89hpes32h8g2", },
1546 	{ .compatible = "idt,89hpes48h12", },
1547 	{ .compatible = "idt,89hpes48h12g2", },
1548 	{ .compatible = "idt,89hpes48h12ag2", },
1549 	{ .compatible = "idt,89hpes16h16", },
1550 	{ .compatible = "idt,89hpes22h16", },
1551 	{ .compatible = "idt,89hpes22h16g2", },
1552 	{ .compatible = "idt,89hpes34h16", },
1553 	{ .compatible = "idt,89hpes34h16g2", },
1554 	{ .compatible = "idt,89hpes64h16", },
1555 	{ .compatible = "idt,89hpes64h16g2", },
1556 	{ .compatible = "idt,89hpes64h16ag2", },
1557 
1558 	{ .compatible = "idt,89hpes12t3g2", },
1559 	{ .compatible = "idt,89hpes24t3g2", },
1560 
1561 	{ .compatible = "idt,89hpes16t4", },
1562 	{ .compatible = "idt,89hpes4t4g2", },
1563 	{ .compatible = "idt,89hpes10t4g2", },
1564 	{ .compatible = "idt,89hpes16t4g2", },
1565 	{ .compatible = "idt,89hpes16t4ag2", },
1566 	{ .compatible = "idt,89hpes5t5", },
1567 	{ .compatible = "idt,89hpes6t5", },
1568 	{ .compatible = "idt,89hpes8t5", },
1569 	{ .compatible = "idt,89hpes8t5a", },
1570 	{ .compatible = "idt,89hpes24t6", },
1571 	{ .compatible = "idt,89hpes6t6g2", },
1572 	{ .compatible = "idt,89hpes24t6g2", },
1573 	{ .compatible = "idt,89hpes16t7", },
1574 	{ .compatible = "idt,89hpes32t8", },
1575 	{ .compatible = "idt,89hpes32t8g2", },
1576 	{ .compatible = "idt,89hpes48t12", },
1577 	{ .compatible = "idt,89hpes48t12g2", },
1578 	{ },
1579 };
1580 MODULE_DEVICE_TABLE(of, idt_of_match);
1581 
1582 /*
1583  * idt_driver - IDT 89HPESx driver structure
1584  */
1585 static struct i2c_driver idt_driver = {
1586 	.driver = {
1587 		.name = IDT_NAME,
1588 		.of_match_table = idt_of_match,
1589 	},
1590 	.probe = idt_probe,
1591 	.remove = idt_remove,
1592 	.id_table = idt_ids,
1593 };
1594 
1595 /*
1596  * idt_init() - IDT 89HPESx driver init() callback method
1597  */
1598 static int __init idt_init(void)
1599 {
1600 	/* Create Debugfs directory first */
1601 	if (debugfs_initialized())
1602 		csr_dbgdir = debugfs_create_dir("idt_csr", NULL);
1603 
1604 	/* Add new i2c-device driver */
1605 	return i2c_add_driver(&idt_driver);
1606 }
1607 module_init(idt_init);
1608 
1609 /*
1610  * idt_exit() - IDT 89HPESx driver exit() callback method
1611  */
1612 static void __exit idt_exit(void)
1613 {
1614 	/* Discard debugfs directory and all files if any */
1615 	debugfs_remove_recursive(csr_dbgdir);
1616 
1617 	/* Unregister i2c-device driver */
1618 	i2c_del_driver(&idt_driver);
1619 }
1620 module_exit(idt_exit);
1621